1. Technical Field
The invention relates generally to conveyor chain assemblies, and more particularly to open area conveyor chain assemblies.
2. Related Prior Art
It is generally known to provide a conveyor chain assembly including a plurality of molded plastic modules, the modules including a large number of link ends on their forward and rearward ends and an upper surface for supporting articles to be conveyed by the chain assembly. The link ends have axially aligned bores intended to house chain pins which extend through the bores and connect the modules together. It is also generally known to provide a conveyor chain assembly comprising modules configured so as to allow flow of fluid through the conveyor assembly. Such conveyor assemblies can be useful for the transport of products such as food through freezing or drying chambers wherein cold or dry air is caused to flow through the chain conveyor. These conveyor assemblies are also used in connection with the transport of products through heating chambers, steaming chambers or washing apparatus as well as in other similar applications. U.S. Pat. No. 4,556,142, which issued to Lapeyre on Dec. 3, 1985, illustrates an example of such an open area conveyor assembly including a plurality of modules linked together by a plurality of chain pins. U.S. Pat. No. 3,870,141, which issued to Lapeyre et al. on Mar. 11, 1975, illustrates another example of an open area conveyor assembly including a plurality of modules linked together by a plurality of chain pins.
U.S. Pat. No. 4,159,763, which issued to Kewley et al. on Jul. 3, 1979, discloses another example of an open area conveyor assembly including a plurality of modules linked together by a plurality of chains pins. The conveyor modules illustrated in that patent include a design wherein a portion of the connecting chain pin is exposed to the flow of fluid through the assembly and is available for visual inspection. In some applications such open chain pin designs can be desirable to facilitate cleaning of the conveyor assembly and to permit visual inspection of the conveyor assembly. More particularly, in applications wherein a modular conveyor assembly is used to carry food stuffs or other articles for human consumption, or in other applications requiring sanitary operating conditions, the conveyor assembly must be cleaned and inspected for cleanliness. For example, in the meat and poultry industries, government regulations require inspection of conveyor assemblies for cleanliness. Other constructions of modules for use in a conveyor assembly and which incorporate an open pin design are shown in U.S. Pat. No. 4,832,187, which issued to Lapeyre on May 23, 1989; U.S. Pat. No. D286,136, which issued to Schroeder et al. on Oct. 14, 1986; and U.S. Pat. No. D282,907 which issued to Schroeder et al. on Mar. 11, 1986.
Among the relevant design criteria for a modular conveyor assembly is the provision of a drive mechanism for advancing the conveyor assembly and the provision of a module having a drive surface adapted to be engaged by the drive mechanism. The conveyor assembly disclosed in U.S. Pat. No. 4,865,183, which issued to Hodlewsky et al. on Sep. 12, 1989, illustrates modules having end links providing a drive surface adapted to be engaged by a sprocket tooth of a drive sprocket. The conveyor assemblies illustrated in the aforementioned U.S. Pat. No. 4,556,142, include modules which have spaced apart link ends and which provide drive surfaces defined by structure located intermediate the spaced link ends. The conveyor chain illustrated in U.S. Pat. No. Re. 30,341, which reissued to Lapeyre on Jul. 22, 1980, includes modules having link ends which provide generally cylindrical drive surfaces adapted to be engaged by a sprocket tooth of a drive sprocket.
Further examples of conveyor assemblies are also illustrated in the following U.S. Patents: U.S. Pat. No. D270,201, which issued to Hodlewsky et al. on Aug. 16, 1983, illustrates a module for use in a conveyer assembly which incorporates a design to enclose the connecting chain pins. U.S. Pat. No. D284,640, which issued to Schroeder et al on Jul. 15, 1986, illustrates a module for use in a conveyor assembly which incorporates a design to enclose the connecting chain pins.